Ecotoxicology

Ecotoxicity network

In the context of the framework directive on water (2000/60/EC), the main discharges are studied in detail using a battery of tests to assess the capacity of the receiving water mass to dilute the toxic load provided. The body of water is in fact the new unit for evaluating whether or not the environmental objectives introduced by the framework directive meet the environmental targets. It is at this level that the targets are set and that the risk of them not being met is evaluated in terms of the management plan. It is also at this level that the environmental effectiveness of the measures (actions) taken by managers is evaluated. The aim of the assessment is to determine the reason for not meeting the targets and the bioassays constituting the adequate tools in this context. From 2005, the “ecotoxicity” network for surface waters in the Walloon region has been adapted to meet these new requirements by focusing on the bodies of water requiring a more in-depth study in order to better understand the pressure-impact links. In this context, the ecotoxicity department:

• Measures the toxicity of the industrial effluents and the receiving surface waters (upstream/downstream of the emission);
• chooses the tests which, when grouped together, are most suitable for describing the toxicity of the effluents from specific industrial sectors;
• studies the capacity of rivers to dilute the toxic load provided by these industrial effluents;

applies these tests as a tool for monitoring the effectiveness of the treatment of effluents.

Sediment toxicity

Sediment is the ultimate reservoir for many one-off (industrial or urban effluents, derelict industrial sites) or diffuse chemical pollutants (agricultural pesticides). Thus, they are a “memory” of the contamination. Conversely, they can also be a source of contamination.
Bioassays are very useful for assessing the actual condition of sediment in which both known and unknown contaminants are present at sufficient concentrations to lead to the toxicity of the organisms tested. The combination of three evaluation methods (chemical, bioassays and ecological – the “triad” approach) can provide a response which cannot be obtained from any of the methods taken individually.

• Whole sediment tests with organisms infected with sediment;
• application of a set of aquatic ecotoxicological tests on interstitial waters and sediment leachates.

Biota contamination

To meet the obligations of the framework directive on water (Directive 2000/60/EC) and its daughter directives, Member States are required to evaluate the chemical state of bodies of surface water. In this context, some environment quality standards (EQS) have been set regarding biota (fish, invertebrate) by directive 2008/105/EC and by directive 2013/39/EU.
In order to meet these challenges, the ecotoxicology department monitors bodies of surface water using the “biota” matrix, specifically concerning the sampling of organisms (fish and invertebrate), the preparation of samples for analyses (dissection, pool formation, lyophilisation, etc.) and the detection of priority substances for which EQS have been set in this matrix by directive 2008/105/EC and directive 2013/39/EU. In addition, an element devoted to developing invertebrate caging techniques is also being validated as part of this project. In fact, caging may constitute an alternative method to the sampling of organisms, particularly in terms of sites where the species in question are absent.

Endocrine disruption

Endocrine disruptors, according to the WHO’s definition, are exogenous substances which alter the functions of endocrine systems and, as a result, lead to dangerous effects for organisms and populations.

Endocrine disruptors are substances with varied structures. They include a wide variety of chemical classes which make systemic research and studies difficult, hence the interest from these types of substances in using tools based on the effect in a screening approach to guide the chemical monitoring.

The bioassays used by the department are YES (Yeast Estrogen Screen) and YAS tests (Yeast Androgen Screen). These mechanistic tests, which use yeast genetically modified by the insertion of the human estrogen and androgen receptor, can be used to quantify (anti)-estrogenic (YES) and (anti)-androgenic activity (YAS).

Toxicity of chemical substances

Bioassays on chemical substances are carried out to support the examination of environmental samples (complete the database, set the boundary conditions) to help companies by quantifying the toxicity of formulations using simple tests and to assess and update testing systems (comparing responses from different testing systems).

Inventory of priority and dangerous priority substances

The department is responsible for performing campaigns to sample and characterise industrial effluents from the main establishments from Walloon’s large industrial basins to prepare an inventory of emissions, discharge and accidental losses of priority substances and other pollutants included in the annexes of the European framework directive on water (directive 2000/60/EC and its daughter directives: 2005/108/EC and 2013/39/EU).

Reference organisation

The ISSeP is the reference organisation for the Walloon region for water, air, and waste. The ecotoxicology department actively participates in the mission.

Updating of methods and validation

• • Study of the critical points of tests;
  • adaptation of procedures and automation;
  • validation of new tests, inter-comparison.

Quality assurance

The ecotoxicology laboratory is ISO 17025 accredited for several parameters (Belac accreditation number: 060-TEST-ISO17025). The studies and tests are performed in line with international standards.